Purina Pro Plan vs Hill's Science Diet (2026)

Pro Plan and Science Diet are close enough on paper that we name no winner. Below is what can be checked, line by line; the choice rests on those details and on what your dog eats well.

How we chose: we did not feed or test either brand; we read each maker's AAFCO statements and staffing claims and searched the recall lists. Cards were sold by Amazon.com and in stock on September 28, 2026.

Pro Plan and Science Diet side by side

Prices are Amazon's, as of the time shown, and subject to change. Details

Who makes them

Purina Pro Plan is made by Nestlé Purina; its pages note that "all Nestlé Purina trademarks" are owned by Société des Produits Nestlé. Hill's describes itself on its company page as "a Colgate-Palmolive Company." Both sell a veterinary prescription range alongside the store-shelf line compared here (Pro Plan Veterinary Diets and Hill's Prescription Diet); those are for your vet to choose and are not part of this comparison.

The AAFCO statements, line by line

The FDA explains that a "complete and balanced" food must either meet an AAFCO nutrient profile or pass a feeding trial using AAFCO procedures. AAFCO's label guide shows the two wordings: "formulated to meet" for the first, "animal feeding tests using AAFCO procedures substantiate" for the second.

Both brands use the feeding-test wording on every product page we read:

• Adult dog. Pro Plan Complete Essentials Shredded Blend Chicken & Rice and Science Diet Adult Chicken & Barley: feeding tests, maintenance of adult dogs. Purina lists 369 kcal per cup, Hill's 365.
• Senior dog. Pro Plan Adult 7+ and Science Diet Adult 7+: feeding tests, maintenance of adult dogs. AAFCO has no senior life stage, which our senior dog food guide explains.
• Kitten. Pro Plan Kitten Chicken & Rice and Science Diet Kitten: feeding tests for growth and for pregnant or nursing cats. Purina lists 633 kcal per cup, Hill's 407, a big difference in how much a scoop delivers. Our best kitten food guide covers kitten statements in more detail.

Feeding trials are the stronger form of evidence, but not the only acceptable one. A Tufts veterinary nutritionist's puppy food checklist says "feeding trials are ideal," while a formulated diet from a manufacturer that meets its other criteria "should be fine as well." Purina's nutrition philosophy page says most of its products go beyond the minimum standards by "voluntarily following" AAFCO's feeding-trial guidelines.

Large-breed puppies: where the wording differs

Since 2016, AAFCO has asked growth and all life stages dog foods to say whether they cover dogs that will weigh 70 lb or more as adults. Tufts' Petfoodology explains why: large-breed puppies "are more sensitive to an excess or shortage of calcium while their bones are growing."

Here the two brands read differently:

• Pro Plan Large Breed Puppy: "complete and balanced nutrition for all life stages, including growth of large sized dogs (70 lb. or more as an adult)." Pro Plan's regular Puppy Chicken & Rice carries the same phrase.
• Science Diet Puppy Large Breed: "complete and balanced nutrition for growing puppies." Hill's recommends it for "large breed puppies (over 55 lbs when adult) up to 18 months old," but the statement on the product page stops at "growing puppies."

That does not mean the Hill's food is wrong for a big puppy; Hill's designed it for exactly that dog, and the bag may carry fuller wording than the web page.

It does mean that if you want the large-dog phrase in writing, Pro Plan's page has it and Hill's page, as of September 2026, does not. Our best puppy food guide covers large-breed growth in more depth, including Tufts' advice to keep large breeds on puppy food until 18 months.

The WSAVA questions: nutritionists and research

The WSAVA Global Nutrition Committee's guidelines suggest asking any pet food company four things. The first is "Do they employ a Nutritionist?", defined as someone with "a PhD in Animal Nutrition or Board Certification by the American College of Veterinary Nutrition (ACVN)" or its European equivalent. The others cover who formulates the diets, what quality control is done, and whether the company publishes research.

Here is what each company's own pages say. We quote them rather than grade them:

• Hill's says on its company page: "of the 94 diplomates in the American College of Veterinary Nutrition, Hill's employs four, along with two veterinarians who are residency-trained in clinical nutrition." It adds that its "staff of PhD nutritionists, food scientists, flavorists and veterinarians" take an evidence-based approach, and that "over 200 scientists and 900+ dogs and cats" work at its Global Pet Nutrition Center.
• Purina says on its Pro Plan nutrition page that Pro Plan "is backed by a team of more than 500 nutritionists, veterinarians, and scientists." Its quality page describes a seven-step quality process and "over 100,000 quality checks per day." The Pro Plan pages we read do not say how many of its nutritionists are ACVN board-certified.

WSAVA adds that if a manufacturer "cannot or will not provide any of this information, veterinarians and owners should be cautious about feeding that brand." Both companies publish enough to answer the first question in some form. For a precise answer, such as how many board-certified nutritionists work on Pro Plan specifically, WSAVA's approach is to ask the company directly.

Recall records

We searched the FDA's recalls, market withdrawals and safety alerts list, which covers company announcements posted from October 2017 to September 2026, for both brands.

Hill's has two entries, both for the same problem. On January 31, 2019, Hill's recalled select canned dog foods for "potentially elevated levels of vitamin D," which it traced to "a supplier error." The list included Science Diet and Prescription Diet canned dog foods; Hill's said "no dry foods, cat foods, or treats are affected." The recall was expanded in May 2019, and the FDA page now says the recall "has been completed" and terminated.

Purina Pro Plan had no entry in that FDA list. That covers only announcements the FDA posted in that period; it is not a full history of either brand.

Neither brand appears on our own pet product recall page, which tracks FDA and CPSC pet recalls from January 2024 to September 28, 2026. If a recall is announced, Purina's own recall article points owners to the FDA as "a great resource," and so do we.

Which one suits your pet

Choose Pro Plan if you are feeding a large-breed puppy and want the "including growth of large sized dogs" wording in the statement.

Choose Science Diet if you want a company that publishes how many board-certified veterinary nutritionists it employs.

Either works if your dog is a healthy adult: both adult foods are feeding-trial tested for maintenance and sit within 4 kcal per cup of each other. The better food is the one your dog eats reliably, keeps a good body condition on, and your vet is happy with. Any switch between them should be gradual; Tufts' guidance on changing foods is at least a week. If your dog has a medical condition, ask your vet which food fits; this page is general information, not veterinary advice (more on that).

For older pets, both brands' senior lines are compared with Royal Canin and Blue Buffalo in our senior dog food and senior cat food guides. Neither brand's foods here is grain-free.

Related: grain-free dog food and DCM, adult dog food guide (six adult foods, a Pro Plan and a Hill's among them).

Frequently Asked Questions

Does Purina run feeding trials on every food?

Not every one, by its own account. Purina's nutrition philosophy page says "most" of its products voluntarily follow AAFCO's feeding-trial guidelines, so read the statement on each bag rather than assuming it from the brand.

What were the signs in the 2019 Hill's vitamin D recall?

The FDA notice lists vomiting, loss of appetite, increased thirst, increased urination, excessive drooling and weight loss. Owners were told to stop feeding the affected cans and throw them away, or return unopened ones for a refund.

How do I tell whether a recall covers my bag or can?

By the codes. The 2019 Hill's notice identified affected cans by product name, SKU and lot/date code, so keep the bag, or a photo of its code, until it is finished.

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PetProofLab is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. AAFCO statements, calorie figures and staffing claims are the makers' own, from their websites. This comparison is general information and is not veterinary advice.